package com.infinitus.nginxInfo.service.util;


import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;

public class Base64{
	private static char[] base64EncodeChars = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' };

	private static byte[] base64DecodeChars = { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 };

	public static String encode(byte[] data){
		StringBuffer sb = new StringBuffer();
		int len = data.length;
		int i = 0;

		while (i < len) {
			int b1 = data[(i++)] & 0xFF;
			if (i == len) {
				sb.append(base64EncodeChars[(b1 >>> 2)]);
				sb.append(base64EncodeChars[((b1 & 0x3) << 4)]);
				sb.append("==");
				break;
			}
			int b2 = data[(i++)] & 0xFF;
			if (i == len) {
				sb.append(base64EncodeChars[(b1 >>> 2)]);
				sb.append(base64EncodeChars[((b1 & 0x3) << 4 | (b2 & 0xF0) >>> 4)]);
				sb.append(base64EncodeChars[((b2 & 0xF) << 2)]);
				sb.append("=");
				break;
			}
			int b3 = data[(i++)] & 0xFF;
			sb.append(base64EncodeChars[(b1 >>> 2)]);
			sb.append(base64EncodeChars[((b1 & 0x3) << 4 | (b2 & 0xF0) >>> 4)]);
			sb.append(base64EncodeChars[((b2 & 0xF) << 2 | (b3 & 0xC0) >>> 6)]);
			sb.append(base64EncodeChars[(b3 & 0x3F)]);
		}
		return sb.toString();
	}

	public static byte[] decode(String str) {
		byte[] data = str.getBytes();
		int len = data.length;
		ByteArrayOutputStream buf = new ByteArrayOutputStream(len);
		int i = 0;

		while (i < len) { int b1;
		int b2;
		int b3;
		int b4;
		do b1 = base64DecodeChars[data[(i++)]];
		while ((i < len) && (b1 == -1));
		if (b1 == -1){
			break;
		}

		do
			b2 = base64DecodeChars[data[(i++)]];
		while ((i < len) && (b2 == -1));
		if (b2 == -1) {
			break;
		}
		buf.write(b1 << 2 | (b2 & 0x30) >>> 4);
		do{
			b3 = data[(i++)];
			if (b3 == 61) {
				return buf.toByteArray();
			}
			b3 = base64DecodeChars[b3]; 
		}
		while ((i < len) && (b3 == -1));
		if (b3 == -1) {
			break;
		}
		buf.write((b2 & 0xF) << 4 | (b3 & 0x3C) >>> 2);
		do
		{
			b4 = data[(i++)];
			if (b4 == 61) {
				return buf.toByteArray();
			}
			b4 = base64DecodeChars[b4]; 
		}
		while ((i < len) && (b4 == -1));
		if (b4 == -1) {
			break;
		}
		buf.write((b3 & 0x3) << 6 | b4);
		}
		return buf.toByteArray();
	}

	public static void main(String[] args) throws UnsupportedEncodingException {
		String base64Str = encode("001:111111".getBytes("UTF-8"));
		System.out.println(base64Str);
		byte[] bs = decode(base64Str);
		System.out.println(new String(bs, "UTF-8"));
	}
}